Repairing



(No Model.)

' J PEDDER. Repairing Steel and other Gruoibles.

Patented April 5, BSSL III-m "rats ATENT Fries. 1

JOHN PEDDER, OF PITTSBURG, PENNSYLVANIA.

SPECIFICATION forming part of Letters'lPatent No.'239,61 9, dated April 5, 1881.

' Application filed February 17, 1881. (No model.)

rior. Fig. 2 is-a like view, illustrating the samewhen applied to the upper part of the crucible; interior to repair the flux-ring.

Like letters of reference indicate like parts in each.

My invention relates to the repairing of the plumbago crucibles used in melting cast-steel, brass, and other metals and alloys, to enable them to stand longer, so that more heats and a larger amount of steel can be obtained from each crucible, thus reducing the relative cost of crucibles in the manufacture or refining of these metals. These crucibles are generally formed of plumbago or German clay, witha slight portion of sand, and are generally known as plumbago crucibles. These are usually contracted at the mouth, formin ga bulge ashort distance below the mouth to strengthen them and increase their capacity, and are made of difi'erent sizes, to hold from fifty to one, hundred pounds of metal. During the process of melting the metalsthe intense heat, flame, and

draft of the furnaces burn away and wear off the outer surfaces of these crucibles very rapidly, the upper part of the crucibles being most affected in gas-furnaces, and the lower part in coke or coal furnaces. The metal and fluxes containedin the crucibles also .wear away and eat off the interiorof .the crucibles, the metal absorbing a portion of the carbon, and the spiegeleisen and manganese eating or cutting bft'the surface, and often cut-ting what is termed a.flux-ring? all around the crucible, where the different fluxes float on the molten metal. The means heretofore adopted for repairing these crucibleshave all been directed toward building up or increasing the outer surface of the crucible, to prevent the heat and flame from burning them off and makingthem too thin for use. I

The object of my invention is to repair the interior of the crucible, so as to prevent the metals and fluxes from eating through the crucible, and by this means to cause the principal wear to come on the outer surface of the cm cible and enable it to stand more heats.

It consists in forming at any desired place on the interior of the crucible, after it has stood one or more heats, a lining or case composed of plumbago, silicon and plnmbago, or other suitable material, whereby the crucible is built up, so that the metal or fluxes in melting cannot cut through thiscase into and eat off the body of the crucible.

To enable others skilled in the'art to make and use my invention, I will describe .the'same' such as that necessary to melt steel, it is notv liable to damage from any such cause, and water can be used with it without fear of sub-. sequent injury therefrom, and for this reason it is necessary that my improved lining be notformed in the crucible until it has been brought to such high heat. I

In carrying out-1n y improved process of repairing crucibles, I g ,nerally treat the crucible after it has stood but one heat, as the lining formed in the crucible will serve as a protection to its inner surface as long as it is used thereafter, though the crucible may be treated in the same manner at any time subsequent to that heat, if desired. 1 generally form a thin plaster or mortar of ground plumbago and silicon, using about'two parts of plumbago to one of silicon, and mixing them together with a little water, so as to form a plaster which will run, as hereinafter referred to. The plaster may also be formed entirely of plumbago, or

of plumbago mixed with German clay and other suitable materials, and in some cases these difl'erent materials may be used without any plumbago. The plumbago is generally made by the interior of the grinding up oldcrucibles', and thesilieon is a common sand, su'elr as is used in connection with furnaces. In forming a cup or case, a,m

the bottom of the crucible, as shown in Fig. 1,

I place a suflicient quantity of this plaster or mortar in the bottom of the crucible, and t en gradually turn the crucible around, and he plaster will gradually run around the crucible and form a lining from an eighth to threeeighths of an inch all over the base of the crucible,-and around the sides thereof.

If it is desired only to fill up the flux-ring or form a case or lining around the upper part of the crucible to repair the c'rucibles'used in gas-furnaces, as'shown at b, Fig. 2, the crucible is turned on its side and-a sufficient quantity of the plastic compound placed therein, and the crucible is turned, as above described, so that the compound will run around and form a ring, filling the flux-ring, or covering mouth of the pot. The lining may also, if desired, be formed all over the interior of the pot; but this is seldom nec essary. After thelinin g or case has thus been formed it is baked or dried, to give it a hard surface and prevent the steel-scrap from penetrating the case when it is shaken in to fill the crucible. When the crucible, thus lined, is again subjected to the intense heat of the melting-furnace, united firmly therewith, and a hard glazed surface formed all over the case, through which the spiegeleisen, manganese, cannot cut, and as no air or flame can come in contact with the lining, the case will stand any further heats to which the crucible is subjected, and will eii'ectually protect the interior of the body of the crucible, and any subsequent wearwillcome only on the outer surface, thus enabling the crucible to be used for two or than where no inner lining lighter and consequently If any of the steel-scrap punctures the fresh lining, in being shaken into the crucible, another lining can be formed in the manner above described, thus filling up any holes made.

Where plumbago forms part of the plastic lining it serves to add carboii to the melting steel, in the same manner as the body of the new crucible, so that it is unnecessary to add the case will be baked or.

or other fluxes sonnueh carbon in thesubsequent heats made imthecruuihle.

WVhere a crucible is cracked, and is generally considered as worthless, by forming the lining within the crucible over the crackgthis lining holds' the crucible together, wholly mending the crack and making the crucible perfectly safe for use. L

Where it is desired to use the crucible immediately after the lining is formed therein, a cap of. heavy paper, sheet-iron, or cast-steel may be placed over the lining, to -prevent the scrap from puncturing it as the crucible is filled. The-paper or other cap will be burned or melt away at the first heat, and leave the hard glazed case or lining in the crucible.

In some cases the cast-steel cap may be placed in the bottom of thecrucible, and the plumhago'and silicon or other material, in a dry or pulverulent state, placed around the cap, a

and upon bringing the'crucible to a high heat this dry material will. be baked or glazed inthe same manner as. the plastic lining. The lining or case may be alsoformed in a rather thick mortar or plaster and molded in'by handor tools; but this is harder to accomplish, and does not give so even a lining as where the thin mortar is used.

What [claim as my invention, to secure by Letters Patent,'is 1 l. The herein-described process of repairing plumhago crucibles, consisting in forming at any desired place in the interior of thecrucible, after it has stood one or more beats, a lining or case composed of plumbago, silicon and plumbago, or other suitable material, to build up the interior of the crucible, substantially as set forth...

and desire 2. In combination with a crucible having a lining or case of plumbago and silicon, or other suitable material, formed at any desired place on the interior of the-crucible, a cap placed-within the crucible to protect or sustain the inner lining, substantially as set forth. In testimony'whereof I, the said JOHN PEI)- DER, have hereunto setni'y hand.

I JOHN PEDDER. Witnesses F. G. KAY,

JAMES I. KAY. 

